GroceryList 
GroceryList is a simple iPhone application built to serve two basic needs:
- Creating and managing a grocery list
- Synchronizing that grocery list between multiple people
The app also serves as an example project for a few different frameworks. It is not meant to be feature-complete, polished, or worth any kind of payment.
If you're only interested in using the app, you can jump straight to getting it built.
(Icon created by @brender.)
Synchronization
The app stores and synchronizes its grocery list using a GitHub repository, since it's easier than writing a synchronization service, and because Git and the GitHub API already support atomic changes. This also means the list is editable from the web, without any need to build a custom web app.
List Format
The grocery list repository follows a fairly simple structure. Each grocery store is represented by a text file of the same name, and those files contain newline-separated lists of grocery items.
For example, the repository could be comprised of these files:
Costco
Safeway
Target
Each file will contain items like this:
Bread
~Crackers~
Peanut butter
Item names with a tilde on either side (~Crackers~ in the above example) have
been "crossed off" of the list, but not yet deleted.
The same item name may appear in multiple store files. Those separate entries will be collapsed into one visible item within the app.
Frameworks
The GroceryList app was built partly as a "real world" demonstration of several frameworks, including:
- Mantle, a lightweight model framework
- ReactiveCocoa (RAC), for functional reactive programming in Cocoa
- ReactiveCocoaLayout, a RAC library for UI layout
- ReactiveViewModel, a RAC library for implementing Model-View-ViewModel
- octokit.objc, a client for the GitHub API (itself built using Mantle and ReactiveCocoa)
Specific libraries aside, the app also serves as a general example of functional reactive programming (FRP) and Model-View-ViewModel (MVVM) in Cocoa.
Using the App
GroceryList is a personal project, not an App Store-quality download. To actually use it, and share your list with specific people, there are a few hoops you'll need to jump through first.
Before anything else, make sure to run script/bootstrap in your local copy of
the repository. This will automatically clone all submodules used in the
project.
Starting the List
Since the app is built on GitHub, it requires a GitHub repository that all users (you, and anyone you want to share the list with) will have permission to push to.
First, create the repository. It can be public or private—just keep in mind the privacy setting when adding grocery items or stores.
Due to a known bug in the app, you must have at least one file in the repository before using it. You can choose to initialize it with a README, or create the file by hand (following the list format), just as long as the repository is not empty.
Finally, add anyone with whom you want to share the list as collaborators on the repository.
Creating an OAuth Application
To be able to log in through the app, it must be configured as a GitHub OAuth
application. Simply register a new
application, making sure to enter
grocery-list://auth as the "Authorization callback URL."
After registration, you'll have to add the client ID and secret to the project's build settings.
Required Build Settings
Because the author is lazy, the project won't build until (effectively) hardcoded with certain settings. This is accomplished with a custom Xcode configuration file that is specifically ignored by Git.
In your local clone of the repository, inside the Configuration folder, create
a file named UserSettings.xcconfig. In it, add a line like the following:
GCC_PREPROCESSOR_DEFINITIONS=$(inherited) GCY_LIST_REPOSITORY=username/grocery-lists GCY_CLIENT_ID= GCY_CLIENT_SECRET=
Replace the value of GCY_LIST_REPOSITORY with the actual full name of the
repository containing the list you created. Fill in
GCY_CLIENT_ID and GCY_CLIENT_SECRET with the details from the OAuth
application you registered.
After the configuration file has been saved, you should be able to open the project and build.
Distribution
The most straightforward way to get up and running with your customized version of the app is to build it directly to the device of anyone interested in sharing your grocery list.
However, it may be easier over the long term to use a (totally optional) service like HockeyApp or TestFlight for distributing builds.
License
This project is released under the MIT license.